Induction coil



v. w. THOMAS INDUCTION COIL Septo w, 1935.

Filed Nov. 12; 1934 llll'llf Patented Sept. 17, 1935 INDUCTION COILVictor W. Thomas, Waukegan, Ill., assigner to E. A. Harrington,Waukegan, Ill., trustee Application November l2, 1934, Serial No.752,567

14 Claims. (Cl. JJM- 361) UNITED STATES PATENT GFFICE This inventionrelates in general to induction coils for ignition apparatus forinternal combustion engines and has more particular reference to animproved casing for housing and disposing the primary and secondarycoils.

An important object of this invention is in the provision of a casing inwhich the primary and secondary coils are separately mounted, thesecondary coil in a sealed container, and the pril() mary coil in aremovable element which includes the magnetic core.

A further object of the invention is in the provision of a primaryignition coil which is wound on a core providing air spaces on bothsides of the primary winding for cooling it.

Further objects of the invention are in the improved means for sealingthe parts of the coil casing; in improved means for holding the coilparts in place, in supporting the coil structure; in

2U connecting the coils to the terminals; and in general in producingthe construction herein shown and described.

In the accompanying drawing, Fig. 1 is a sectional vieW of an ignitioncoil embodying this 25. invention;

Fig. 2 is a top view;

Fig. 3 is a side elevation;

Fig. 4 is a sectional detail of a s-econdary coil connection; and

30, Fig, 5 is an enlarged section showing the primary coil and itscontainer.

In ignition coils it has been the practice to mount the primary andsecondary coil elements in a container and to ll the space not occupied351 by the coils with a plastic insulating material which hardens but issubject to heat and if the coil becomes sufficiently heated theinsulating material becomes plastic, expands and exudes from thecontainer.

40 The present invention proposes to overcome this objection by mountingthe secondary coil `in a chamber closed to the atmosphere, without anyplastic insulating material; to separate the primary and secondary coilsentirely; and to 415 wind the primary coil on a core element which isbodily removable therewith, the element tting loosely within thesecondary coil and having a core which provides an air space at theinside of the primary winding sothat the pri- 50 mary Winding is cooledfrom the inside and outside and does not communicate its heat nor thatof the magnetic core to the secondary winding at any time.

Referring now more particularly to the draw- 55 ing, a casing element I0preferably formed of bakelite or other similar water-proof insulatingmaterial, is preferably cast or molded in the form of a hollow ringhaving an outer wall I I with outside liutings I 2, and an inner wall I3having a shouldered portion I4 at a distance 5 from the bottom of thecontainer ring thus formed.

A secondary coil winding I5 is made of a proper size to t within thecasing IG and upon the inner shell i3 against the shoulder I4. In the 10outer end of this container a short shell section i5 is placed againstthe end of the coil I5 and a cap I7 is applied to the ends of the innerand outer walls or shells I2 and I3 and against the outer end oi theshort shell i6 holding the coil l5 I5 firmly in place intermediate theends of the casing member IQ.

In the cap are grooves I9 and 2D for seating the ends of the walls I3and I2 and in the grooves are gaskets 2I and 22 or a sealing compound 20for making an air-tight joint for the secondary coil container. The capis held firmly in place at the end of the coil member Il) in anysuitable means as by a sealing ring 22 in the form of a flange of whichone edge is seated in a circular depression 23 of the outer side of thecasing member IB, the other edge 24 of the flange being bent over theouter edge of the cap I'I.

This construction provides a sealed chamber for holding the secondarywinding I5 tightly in 30 place and the cap il has a central opening 25slightly less in diameter than the inner diameter of the shell i3 whichis also open at the other end of the member I0 for inserting the primarywinding.

For the primary winding 3U there is a hollow core member 3| alsopreferably made of insulating waterproof material such as bakelite. Theinterior opening 3i of this core member 3| is preferably rectangular toreceive a laminated magnetic core 33 which is secured tightly in placetherein and the outer angular corners 34 of the core are roundedoutwardly beyond the sides to provide projections upon which the primarywindings t@ will rest, leaving a space below the windings and betweenthe projections 34. At the ends of the core 3l are flanges 35 withopenings 33 therein communicating with the spaces below the coilwindings and between the projections 34. These flanges 35 also t withinthe inner shell I3 so that only angular or corner portions l are inengagement with the wall I 3, leaving spaces therebetween at the outsideof this primary core member so that there is a passage 55 entirelyaround the outside of the primary winding Within the inner shell I3.

One end of the primary core member abuts the cap I1 about its opening 25and the other end of the core member is engaged by a hollow clampingring 40 which is held in place on the end oi the coil member IIJ byfastening screws 4 I leaving the center thereof unobstructed for thepassage of air to the primary winding. In this fastening ring 40 areopposite terminals 42 and 43 connected by wires 44 and 45 to the ends ofthe primary Winding 30.

At one end of the casing member l is a terminal 41 extending in a recess39 of the clamping ring 4I), and connected by a conductor 48 with oneend of the secondary coil I and the other end of the secondary coil I5is connected by a conductor 43 with a screw contact terminal 5l)preferably having a head 5I embedded in the outer wall I2 of the coilmember Il), the end of the conductor 43 extending through the screwterminal 5B and soldered or otherwise connected therein to make asubstantially fluid-tight joint. Surrounding the screw terminal 50 is aboss or flange 52, preferably circular, for seating a terminal plug 53in which a secondary terminal wire 54 is connected. This wire has vaninsulating cover 55 which fits tightly in an opening 5S abutting aninserted internally threaded socket 51 adapted to engage the screwterminal 5&3. To make an electrical connection a screw 5B is insertedthrough the bottom of the member 51 into the end of the conductor wire54, thereby binding it tightly in place and making a satisfactoryelectrical connection therefor. With this construction even if theconductor 54 does not make a fluid-tight connection with the plug member53, the terminal member 50 does make a fluidtight connection with thewall of the casing member II) so that there is no leakage of the casingmember I0 due to the electrical connec tion. The other terminals 42, 43and 41 may be connected to their corresponding conductors in a mannersimilar to that of the terminal 5B, or in any other suitable manner. Anelectrical conductor 45 commonly connects primary and secondaryterminals 42 and 41 when the coil is in use.

In order to support this induction coil casing there is a lateralprojection 60 from the outer wall II which has a plurality of spacedperforations EI to be engaged by corresponding openings of angularbrackets 62. To support the coil from one end, the cap is provided withprojections 63 having spaced openings 64 for engaging the correspondingopenings of one or two brackets as shown in Fig. 2, the brackets beingsuitably perforated or slotted for attachment to any suitable support.

With this construction it will be apparent that the secondary winding isentirely enclosed within a substantially waterproof ring casing, thatthe primary winding is entirely separate and distinct from the secondaryand is mounted on a core in a passage to receive cooling air both insideand outside of the primary winding. Thus the greatest source of heat forthe secondary winding not only is spaced from it but has an air coolingpassage between it and there is little danger of overheating of thesecondary winding or' overheating in the chamber containing thesecondary winding. The primary and its mounting are also readilyremovable from the coil structure by simply disengaging the fasteningscrews 4I, which loosens the clamping ring 4t; and the primary and itsconnections may be bodily removed Without in any way affecting thesecondary. The primary winding or the core may therefore be easilyremoved or replaced when desired.

I claim:

l. An induction coil having a casing with a 5 cover having an openpassage therethrough, a Winding in the casing around the passage, a coreholder with ribs to fit in the passage, a winding on the ribs of theholder leaving air spaces between the winding and the core for coolingthe winding.

2. An induction coil having a closed casing with an open passagetherethrough, a winding in the casing around the passage; a magnetizablecore and a winding for the passage, and a holder therefor; the holderhaving ribs upon which the winding is wound leaving air spaces extendinglongitudinally in the passage for cooling the winding.

3. In an induction coil, a closed casing having 2() a winding thereinyand an open passage therethrough, a hollow holder, a magn-etizable coretherein, a winding on the holder, means spacing the winding from thesurface of the holder to leave lengthwise air passages between thewinding and holder, and the holder and its winding fitting in the casingpassage to leave an air space surrounding the winding in the passage.

4. In an induction coil, a casing having a winding and an open passagethrough it, a winding holder to iit in. the passage having winding ribsand openings at the ends between the ribs, and a winding on the holder'leaving air spaces surrounding the winding and between the winding andthe holder communicating with the openings for cooling the winding.

5. In an induction coil, a casing having an open passage through it, awinding in the casing, a holder therefor having winding ribs and endsupports in the passage, a winding on said ribs, and o the end supportshaving openings at the ends between the ribs to form air passages withinthe winding and openings about the edges to provide air passages aroundthe winding in said casing paSSage.

6. In an induction coil, a ring casing having a cover extending over theinner edge of the casing,

a winding in the casing, a winding and core holder having an end toengage the cover in the ring opening, and a plate to engage the edge ofthe holder at the other end of the casing leaving a central opening forthe passage of air through the ring passage and through said holder.

7. In an induction coil, a casing having a central passage, a coverengaging over the inner and outer edges of the casing, a winding in thecasing, means for clamping the cover to the casing, an inner core andwinding and a holder therefor to lit in the passage and engage the coverat one end, and a lid at the other end for engaging the holder to conneit removably in place.

8. In an induction coil, a casing having inner and outer walls with ashouldered portion at the inside of the casing on the inner Wall, awinding tting the inner wall and abutting the shouldered 65 portion, ashell section abutting the other side of the winding and on the innerwall, a cover engaging the outer end of the shell section, and meansholding the cover on the casing and the winding between the ends of thecasing.

9. In an induction coil, a casing having inner and outer walls, awinding in the casing, a cover having grooves to seat the inner andouter walls, sealing means in the grooves, and a gripping band withinwardly turned edges to engage the cover and the outer edge of thecasing to hold them together.

10. In an induction coil, a casing having a central opening, a Windingin the casing, means forming a stop at the margin of one end of theopening, a magnetizable core, a holder therefor engaging said stop andhaving longitudinal outer ribs, end flanges and openings between theribs thereof, a winding on the ribs and between the fianges, the flangeshaving angular corners trimmed to fit in the opening in the casing andhaving openings between the corners at the margins of the flanges,thereby providing air spaces above and below the winding, and means toengage the end of the holder opposite said stop for holding it in therecess.

l1. In an induction coil, a bakelite case having inner and outer tubularwalls, a Winding therein, a cover for holding the cover on the case inair sealing engagement, means providing fluid-tight contact terminalsconnected with the Winding through the walls of the case, a magnetizablecore, a holdei` therefor, a Winding on the holder, means for confiningthe holder within the inner tubular Wall comprising a clamping ringhaving Contact terminals projecting therefrom connected with the windingon the holder.

12. In an induction coil, a tubular hollow casing, a cover therefor,means binding the cover to the casing, a Winding in the casing havingeX- ternal contact terminals projecting from the casing, a secondexposed winding removably mounted in the hollow of the casing, meanscomprising a perforated projection from the outside of the casing,perforated projections on the cover and perforated brackets to fit saidprojections for supporting the casing.

13. In an induction coil, a bakelite insulating 5 case, a windingtherein having threaded metal terminals cast in and projecting from thecase, the ends of the winding Abeing electrically connected to theterminals, a plug connection for said terminal including a threadedsocket to iit the terminal, a plug member for the socket, a coveredelectrical conductor inserted in the plug member and a connecting screwinserted into the conductor, from the inside of the socket and makingelectrical contact with the said projecting terminal.

14. An induction coil comprising an insulating case having inner andouter tubular walls, a secondary winding mounted on the inside of theinner wall, means holding the Winding in intermediate position thereonincluding a cover, a primary winding and a magnetizable core, a holderof insulating material therefor having an interior bore for the core,the holder being mounted within the inner tubular wall and the coverforming a stop therefor at one end, a clamping ring for engaging theholder at the other end of the case, the ring having terminalsprojecting therefrom and connected to the ends of the primary windingand movable with the primary Winding holder when it is applied to andremoved from the case.

VICTOR W. THOMAS.

